In-vehicle seal integrity verification system

ABSTRACT

A seal integrity verification system includes a pressure source, a valve, and a pressure sensor. The pressure source is fluidly connected to a housing having at least one sealing member. The valve is fluidly connected to the pressure source and the housing. The valve is movable between a first open position and a closed position. The pressure sensor is arranged to provide a first signal indicative of a pressure within the housing.

CROSS REFERENCE TO RELATED APPLICATION

This divisional application claims priority to U.S. application Ser. No.15/894,392, filed Feb. 12, 2018, which is incorporated herein byreference in its entirety.

BACKGROUND

Vehicles may be provided with a power steering system having anelectronic assist mechanism. The electronic assist mechanism provides adriving force that is transmitted to a portion of the power steeringsystem to assist or amplify a steering force applied by an operator ofthe vehicle. The electronic assist mechanism may be disposed close to aroad surface or an external environment of the vehicle requiring theelectronic assist mechanism to be sealed to inhibit the intrusion ofwater or foreign objects into the power steering system.

SUMMARY

According to an embodiment of the present disclosure, a seal integrityverification system is provided. The seal integrity verification systemincludes a pressure source, a valve, and a pressure sensor. The pressuresource is fluidly connected to a housing having at least one sealingmember. The valve is fluidly connected to the pressure source and thehousing. The valve is movable between a first open position and a closedposition. The pressure sensor is arranged to provide a first signalindicative of a pressure within the housing.

According to another embodiment of the present disclosure, an electricpower steering system is provided. The electric power steering systemincludes an electric power steering unit and a seal integrityverification system. The electric power steering unit has a housing thatis provided with at least one sealing member. The seal integrityverification system includes a pressure sensor, a pressure source, and acontrol unit. The pressure sensor is disposed within the housing and isarranged to monitor a pressure within the housing. The pressure sourceis disposed on the housing and is fluidly connected to the housing. Thecontrol unit is in communication with the pressure source and thepressure sensor.

According to yet another embodiment of the present disclosure, anelectric power steering system is provided. The electric power steeringsystem includes an electric power steering unit and a seal integrityverification system. The electric power steering unit has a housing thatis provided with at least one sealing member. The seal integrityverification system includes a pressure sensor and a pressure source.The pressure sensor is arranged to monitor a pressure within thehousing. The pressure source is fluidly connected to the housing througha valve that is fluidly connected to the pressure source and thehousing. The valve is movable between an open position and a closedposition.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the claims at the conclusion of thespecification. The foregoing and other features, and advantages of thepresent disclosure are apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings in which:

FIG. 1 is an elevation view of an electric power steering system havinga seal integrity verification system according to a first embodiment;and

FIG. 2 is an elevation view of an electronic power steering systemhaving a seal integrity verification system according to a secondembodiment.

DETAILED DESCRIPTION

Referring now to the Figures, where the present disclosure will bedescribed with reference to specific embodiments, without limiting thesame, it is to be understood that the disclosed embodiments are merelyillustrative of the present disclosure that may be embodied in variousand alternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present disclosure.

Referring to FIGS. 1 and 2, an electric power steering system 10 isshown. The electric power steering system 10 may include a steeringmechanism that is disposed within a rack housing 12 and a power assistmechanism 14. The steering mechanism may be protected from an externalenvironment by flexible boots 18 that are disposed at ends of the rackhousing 12. The steering mechanism may include a toothed rack thatlaterally translates responsive to rotation of a gear to move at leastone tie rod 16 to move or pivot at least one vehicle wheel.

The power assist mechanism 14 may be an electric power steering unithaving a housing 20 provided with at least one sealing member 22, suchas a gasket, o-ring, or other type of sealing member. The housing 20having at least one sealing member 22 is sealingly connected to the rackhousing 12. In at least one embodiment, at least one sealing member 22may be a sealed or flanged joint/junction between the rack housing 12and the housing 20.

The electric power steering unit or power assist mechanism may include apower assist actuator and a control unit 24 that are at least partiallydisposed within the rack housing 12 having the flexible boots 18 and/orthe housing 20 having at least one sealing member 22. In the embodimentsshown, the power assist actuator is disposed within the housing 20 andthe control unit 24 is disposed within the rack housing 12 proximate thehousing 20. The control unit 24 may be in communication with powerassist mechanism 14 and may operate the power assist mechanism 14.

The flexible boot 18 and at least one sealing member 22 are provided toat least partially inhibit the intrusion of water or other foreignobjects from entering into at least one of the rack housing 12 and/orthe housing 20.

At least one of the rack housing 12 having the flexible boots 18 and/orthe housing 20 having at least one sealing member 22 may be leak testedto ensure or verify the integrity of the flexible boots 18 and/or atleast one sealing member 22 by an onboard or in-vehicle seal integrityverification system 30. The seal integrity verification system 30 may bearranged to ensure or verify the integrity of the flexible boots 18and/or at least one sealing member 22 while the vehicle thatincorporates electric power steering system 10 is on and operational.

In the embodiment shown in FIG. 1, the seal integrity verificationsystem 30 is disposed on the housing 20. In other embodiments, the sealintegrity verification system 30 may be disposed on at least one of therack housing 12 and/or the housing 20.

In the embodiment shown in FIG. 2, the seal integrity verificationsystem 30 is spaced apart from the rack housing 12 and the housing 20.

The seal integrity verification system 30 is fluidly connected to atleast one of the rack housing 12 or the housing 20 by a port 32 that isdefined by the rack housing 12 or the housing 20 and a first conduit 34that extends between the port 32 and a port 36 of the seal integrityverification system 30.

For ease of description, the seal integrity verification system 30 willbe described as being in communication with the control unit 24 althoughthe seal integrity verification system 30 may be in communication with aseparate control unit that is in communication with the seal integrityverification system 30.

The seal integrity verification system 30 includes a pressure sensor 40,a valve 42, and a pressure source 44. The seal integrity verificationsystem 30 may be at least partially disposed within at least one of therack housing 12 and/or the housing 20, as shown in FIG. 1. The sealintegrity verification system 30 may be provided as an integral unithaving the pressure sensor 40, the valve 42, and the pressure source 44all integrated into a unit housing 46, as shown in FIG. 2.

The pressure sensor 40 is in communication with the control unit 24 andis arranged to monitor a pressure and/or a change in pressure (pressuredecay) within at least one of the rack housing 12 and/or the housing 20.The pressure sensor 40 is arranged to provide a first signal indicativeof a pressure within at least one of the rack housing 12 and/or thehousing 20. The pressure sensor 40 is further arranged to provide asecond signal indicative of a pressure decay within at least one of therack housing 12 and/or the housing 20.

The pressure sensor 40 may be disposed within the housing 20, as shownin FIG. 1. The pressure sensor 40 may be spaced apart from the housing20 and disposed within the unit housing 46, as shown in FIG. 2. Thepressure sensor 40 may be a pressure transducer or other pressuremeasurement device.

The valve 42 is in communication with the control unit 24. The valve 42is fluidly connected to the pressure source 44 and an interior of thehousing 20. The valve 42 may be at least partially disposed on or extendthrough the housing 20, as shown in FIG. 1. The valve 42 may be spacedapart from and fluidly connected to the housing 20, as shown in FIG. 2.

The valve 42 may be an electronically actuated two-way valve orthree-way valve. Should the valve 42 be configured as a two way valve,the valve 42 is movable between a first open position and a closedposition. The first open position may be a position of the valve 42 thatenables a fluid from the pressure source 44 to enter and/or exit therack housing 12 and/or the housing 20. The closed position may be aposition that inhibits a fluid from the pressure source 44 from enteringand/or exiting the rack housing 12 and/or the housing 20.

Should the valve 42 be configured as a three-way valve, the valve 42 ismovable between the first open position, a second open position, and theclosed position. The first open position may be a position of the valve42 that enables the fluid from the pressure source 44 to enter and/orexit the rack housing 12 and/or the housing 20. The second open positionmay be a position of the valve 42 that enables a fluid from the pressuresource 44 to exit the rack housing 12 and/or the housing 20 and bevented through a vent line 48 through a vent 50. The vent 50 may ventinto the passenger compartment of the vehicle or directly to theexternal environment. The closed position may be a position thatinhibits a fluid from the pressure source 44 from entering and/orexiting the rack housing 12 and/or the housing 20.

The pressure source 44 is in communication with the control unit 24. Thepressure source 44 is fluidly connected to at least one of the rackhousing 12 and/or the housing 20 through the valve 42. The pressuresource 44 may be disposed on or disposed proximate the rack housing 12and/or the housing 20, as shown in FIG. 1. The pressure source 44 may bespaced apart from the rack housing 12 and/or the housing 20 and disposedwithin the unit housing 46, as shown in FIG. 2.

The pressure source 44 may be a compressor that is arranged to provide afluid to the rack housing 12 and/or the housing 20 at a positivepressure. The compressor may be arranged to receive air or a fluid froma generally ambient source such as an interior of the vehicle, theengine air cleaner compartment, or another ambient air source.

The pressure source 44 may alternatively be a vacuum source 54 that isarranged to produce or provide a negative pressure within the rackhousing 12 and/or the housing 20. The vacuum source 54 may be a vacuumpump, a vacuum manifold, or other vacuum source that may be providedwith the vehicle. A second conduit 60 extends between the vacuum source54 and the seal integrity verification system 30.

In at least one embodiment, a pressure regulator may be provided tolimit the pressure provided by the pressure source 44.

The control unit 24 may be provided with input communication channelsthat are arranged to receive the first signal and the second signal fromthe pressure sensor 40, a signal indicative of the position of the valve42, and a signal indicative of the operational state of the pressuresource 44. The control unit 24 may be provided with output communicationchannels that are arranged to provide signals or commands to the valve42 to change or vary a position of the valve 42 and to provide signalsor commands to the pressure source 44 to change the operational state ofthe pressure source 44.

The control unit 24 may be provided with at least one processor that isprogrammed to run or perform a seal verification routine to ensure orverify the integrity of at least one of the flexible boots 18 and/or atleast one sealing member 22. Responsive to a request to verify or ensurethe integrity of at least one of the flexible boots 18 and/or at leastone sealing member 22, the control unit 24 may command the valve 42 tomove from the closed position towards the first open position and maycommand the pressure source 44 to operate. Operation of the pressuresource 44 may result in the compressor operating to provide a fluid intoat least one of the rack housing 12 and/or the housing 20 at a positivepressure. Operation of the pressure source 44 may result in the vacuumsource 54 drawing a vacuum or reducing a pressure within at least one ofthe rack housing 12 and/or the housing 20.

Responsive to at least one of a predetermined time period and/or thefirst signal being indicative of an internal pressure within at leastone of the rack housing 12 and/or the housing 20 achieving or beingproximate a predetermined fluid pressure, the control unit 24 maycommand the pressure source 44 to cease operation and may command thevalve 42 to move towards the closed position.

Responsive to the second signal being indicative of a change in pressureor pressure decay within at least one of the rack housing 12 and/or thehousing 20 being greater than a threshold, the control unit 24 mayoutput a warning indicative of a possibly compromised flexible boot 18and/or at least one sealing member 22.

Responsive to the completion of the seal verification routine, thecontrol unit 24 may command the valve 42 to vent the fluid from withinat least one of the rack housing 12 and/or the housing 20. The controlunit 24 may command the valve 42 to move towards the first openposition, should the valve 42 be a two-way valve, or may command thevalve 42 to move towards the second open position should the valve 42 bea three-way valve.

The seal integrity verification system 30 enables an in-vehicle leaktest to ensure or verify seal integrity of various sealing members thatare associated with the rack housing 12 and/or the housing 20 prior tothe intrusion of water or other foreign objects. The seal integrityverification system 30 may perform the seal verification routine atvarious preset intervals or may be manually actuated. The seal integrityverification system 30 utilizes the pressure source 44 to change thepressure to a given value within the rack housing 12 or the housing 20.The seal integrity verification system 30 then utilize the valve 42 toseal the rack housing 12 and/or the housing 20 from the pressure source44 and monitor the pressure decay versus time via the pressure sensor 40to determine a possible leak rate based on the pressure decay. The sealintegrity verification system 30 determines whether the sealing featurespass or fail the seal integrity check based on the possible leak rate.The seal integrity verification system 30 releases the pressure withinthe rack housing 12 and/or the housing 20 at least until an ambientpressure is achieved and seals at least one of the rack housing 12and/or the housing 20 via the valve 42.

While the present disclosure has been described in detail in connectionwith only a limited number of embodiments, it should be readilyunderstood that the present disclosure is not limited to such disclosedembodiments. Rather, the present disclosure can be modified toincorporate any number of variations, alterations, substitutions orequivalent arrangements not heretofore described, but which arecommensurate in scope with the present disclosure. Additionally, whilevarious embodiments of the present disclosure have been described, it isto be understood that aspects of the present disclosure may include onlysome of the described embodiments or combinations of the variousembodiments. Accordingly, the present disclosure is not to be seen aslimited by the foregoing description.

Having thus described the present disclosure, it is claimed:
 1. A sealintegrity verification system, comprising: a pressure source fluidlyconnected to a housing having at least one sealing member, wherein thepressure source is a compressor that is arranged to provide a fluid at apositive pressure in the housing; a valve fluidly connected to thepressure source and the housing, the valve movable between a first openposition and a closed position; a pressure sensor arranged to provide afirst signal indicative of a pressure within the housing, wherein thepressure sensor is arranged to provide a second signal indicative of apressure decay within the housing; and a control unit in communicationwith the pressure source, the valve, and the pressure sensor, thecontrol unit programmed to, responsive to a request to verify anintegrity of at least one sealing member, command the valve to movetowards the first open position and command the pressure source tooperate.
 2. The seal integrity verification system of claim 1, whereinthe control unit is further programmed to command the compressor tooperate to provide the fluid to the housing.
 3. The seal integrityverification system of claim 2, wherein the control unit is furtherprogrammed to, responsive to at least one of a predetermined time periodand the first signal, command the compressor to cease operation andcommand the valve to move towards the closed position.
 4. The sealintegrity verification system of claim 3, wherein the control unit isfurther programmed to, responsive to the second signal being indicativeof the pressure decay being greater than a threshold, output for displaya warning.
 5. The seal integrity verification system of claim 4, whereinthe control unit is further programmed to, command the valve to movetowards the first open position to vent the fluid.
 6. The seal integrityverification system of claim 4, wherein the control unit is furtherprogrammed to, command the valve to move towards a second open positionthat inhibits a fluid from the pressure source to enter the housing andvents the fluid.
 7. A seal integrity verification system comprising: apressure source fluidly connected to a housing having at least onesealing member, wherein the pressure source is a compressor that isarranged to provide a fluid at a positive pressure into the housing; avalve fluidly connected to the pressure source and the housing, thevalve movable between a first open position and a closed position; apressure sensor arranged to provide a first signal indicative of apressure within the housing, wherein the pressure source is a vacuumsource that is arranged to produce a negative pressure within thehousing; and a control unit in communication with the pressure source,the valve, and the pressure sensor, the control unit programmed to,responsive to a request to verify an integrity of at least one sealingmember, command the valve to move towards the first open position andcommand the pressure source to operate.